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10-2. Specifications of communication division
Communication
system
: Asynchronous method
Communication
speed
: 38400,19200,9600,4800,2400bps switching communication speed
Start bit
: 1 bit
Data length
: 7 bit (ASCII mode/PRIVATE mode) or 8 bits (RTU mode/ASCII mode)
Parity bit
: None (RTU mode/ASCII mode), Even (RTU mode/ASCII mode/PRIVATE mode),
Odd (RTU mode/ASCII mode)
Stop bit
: 1 bit (RTU mode/ASCII mode/PRIVATE mode), 2 bits (RTU mode/ASCII mode)
Transmission code
: ASCII (ASCII mode/PRIVATE mode) or Binary (RTU mode)
Error check
: Check sum Ú1…For PRIVATE mode
: CRC-16 …For RTU mode
: LRC …For ASCII mode
Usage signal name
: Send or receive data only, without using control signal
Ú1 Check sum (BCC)
Check sum means, total sum of characters after STX up to ETX is calculated, lower order 8 bits are
split into high and low order 4 bits and are converted to characters from 0 to F and are sent and
received sequentially in high order and low order.
(Example)
,
Character
△ △ △
3 0 0 0 ETX
Tota l s um =
BCC
ASCII
code
20h 20h 20h 33h 30h 30h 2Eh 30h 03h 154h=45
S
T
X
△ △ △ 300
0
E
T
X
B
C
C
4
C
R
L
F
5
B
C
C
△ = Space